Hornady Ammo 300 Blackout 190 Gr Sub-X™Hornady® 300 Blackout Subsonic Ammunition is designed for accuracy and performance below the speed of sound. The new 190 gr Sub-X™ (Subsonic - eXpanding) bullet features a lead core. Long grooves in its gilding metal jacket combine with the bullet’s flat profile and the patented Flex Tip® insert within its hollowpoint cavity to help it expand reliably at low velocities.Performance of the Hornady® 300 Blackout Subsonic load meets or exceeds FBI Protocol terminal ballistic test requirements.